perf build: Remove libbpf pre-1.0 feature tests

The feature tests were necessary for libbpf pre-1.0, but as the libbpf
implies at least 1.0 we can remove these now.

Committer notes:

Modified tools/perf/Makefile.config to better reflect the reason for
failure when the libbpf present is < 1.0 and LIBBPF_DYNAMIC=1 was asked
for.
Signed-off-by: Ian Rogers <irogers@google.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Tested-by: Jiri Olsa <jolsa@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andres Freund <andres@anarazel.de>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Christy Lee <christylee@fb.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Quentin Monnet <quentin@isovalent.com>
Cc: Roberto Sassu <roberto.sassu@huawei.com>
Cc: bpf@vger.kernel.org
Link: https://lore.kernel.org/r/20230116010115.490713-2-irogers@google.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/build/feature/Makefile

@@ -58,13 +58,6 @@ FILES=                                          \
          test-lzma.bin                          \
          test-bpf.bin                           \
          test-libbpf.bin                        \
-         test-libbpf-btf__load_from_kernel_by_id.bin	\
-         test-libbpf-bpf_prog_load.bin          \
-         test-libbpf-bpf_map_create.bin		\
-         test-libbpf-bpf_object__next_program.bin \
-         test-libbpf-bpf_object__next_map.bin   \
-         test-libbpf-bpf_program__set_insns.bin	\
-         test-libbpf-btf__raw_data.bin          \
          test-get_cpuid.bin                     \
          test-sdt.bin                           \
          test-cxx.bin                           \

tools/build/feature/test-libbpf-bpf_map_create.c

-// SPDX-License-Identifier: GPL-2.0
-#include <bpf/bpf.h>
-
-int main(void)
-{
-	return bpf_map_create(0 /* map_type */, NULL /* map_name */, 0, /* key_size */,
-			      0 /* value_size */, 0 /* max_entries */, NULL /* opts */);
-}

tools/build/feature/test-libbpf-bpf_object__next_map.c

-// SPDX-License-Identifier: GPL-2.0
-#include <bpf/libbpf.h>
-
-int main(void)
-{
-	bpf_object__next_map(NULL /* obj */, NULL /* prev */);
-	return 0;
-}

tools/build/feature/test-libbpf-bpf_object__next_program.c

-// SPDX-License-Identifier: GPL-2.0
-#include <bpf/libbpf.h>
-
-int main(void)
-{
-	bpf_object__next_program(NULL /* obj */, NULL /* prev */);
-	return 0;
-}

tools/build/feature/test-libbpf-bpf_prog_load.c

-// SPDX-License-Identifier: GPL-2.0
-#include <bpf/bpf.h>
-
-int main(void)
-{
-	return bpf_prog_load(0 /* prog_type */, NULL /* prog_name */,
-			     NULL /* license */, NULL /* insns */,
-			     0 /* insn_cnt */, NULL /* opts */);
-}

tools/build/feature/test-libbpf-bpf_program__set_insns.c

-// SPDX-License-Identifier: GPL-2.0
-#include <bpf/libbpf.h>
-
-int main(void)
-{
-	bpf_program__set_insns(NULL /* prog */, NULL /* new_insns */, 0 /* new_insn_cnt */);
-	return 0;
-}

tools/build/feature/test-libbpf-btf__load_from_kernel_by_id.c

-// SPDX-License-Identifier: GPL-2.0
-#include <bpf/btf.h>
-
-int main(void)
-{
-	btf__load_from_kernel_by_id(20151128);
-	return 0;
-}

tools/build/feature/test-libbpf-btf__raw_data.c

-// SPDX-License-Identifier: GPL-2.0
-#include <bpf/btf.h>
-
-int main(void)
-{
-	btf__raw_data(NULL /* btf_ro */, NULL /* size */);
-	return 0;
-}

tools/perf/Makefile.config

@@ -565,54 +565,26 @@ ifndef NO_LIBELF
 
       # detecting libbpf without LIBBPF_DYNAMIC, so make VF=1 shows libbpf detection status
       $(call feature_check,libbpf)
+
+      # Feature test requires libbpf 1.0 so we can assume the following:
+      CFLAGS += -DHAVE_LIBBPF_BTF__LOAD_FROM_KERNEL_BY_ID
+      CFLAGS += -DHAVE_LIBBPF_BPF_PROG_LOAD
+      CFLAGS += -DHAVE_LIBBPF_BPF_OBJECT__NEXT_PROGRAM
+      CFLAGS += -DHAVE_LIBBPF_BPF_OBJECT__NEXT_MAP
+      CFLAGS += -DHAVE_LIBBPF_BPF_PROGRAM__SET_INSNS
+      CFLAGS += -DHAVE_LIBBPF_BTF__RAW_DATA
+      CFLAGS += -DHAVE_LIBBPF_BPF_MAP_CREATE
+
       ifdef LIBBPF_DYNAMIC
         ifeq ($(feature-libbpf), 1)
           EXTLIBS += -lbpf
           $(call detected,CONFIG_LIBBPF_DYNAMIC)
-
-          $(call feature_check,libbpf-btf__load_from_kernel_by_id)
-          ifeq ($(feature-libbpf-btf__load_from_kernel_by_id), 1)
-            CFLAGS += -DHAVE_LIBBPF_BTF__LOAD_FROM_KERNEL_BY_ID
-          endif
-          $(call feature_check,libbpf-bpf_prog_load)
-          ifeq ($(feature-libbpf-bpf_prog_load), 1)
-            CFLAGS += -DHAVE_LIBBPF_BPF_PROG_LOAD
-          endif
-          $(call feature_check,libbpf-bpf_object__next_program)
-          ifeq ($(feature-libbpf-bpf_object__next_program), 1)
-            CFLAGS += -DHAVE_LIBBPF_BPF_OBJECT__NEXT_PROGRAM
-          endif
-          $(call feature_check,libbpf-bpf_object__next_map)
-          ifeq ($(feature-libbpf-bpf_object__next_map), 1)
-            CFLAGS += -DHAVE_LIBBPF_BPF_OBJECT__NEXT_MAP
-          endif
-          $(call feature_check,libbpf-bpf_program__set_insns)
-          ifeq ($(feature-libbpf-bpf_program__set_insns), 1)
-            CFLAGS += -DHAVE_LIBBPF_BPF_PROGRAM__SET_INSNS
-          else
-            dummy := $(error Error: libbpf devel library needs to be >= 0.8.0 to build with LIBBPF_DYNAMIC, update or build statically with the version that comes with the kernel sources);
-          endif
-          $(call feature_check,libbpf-btf__raw_data)
-          ifeq ($(feature-libbpf-btf__raw_data), 1)
-            CFLAGS += -DHAVE_LIBBPF_BTF__RAW_DATA
-          endif
-          $(call feature_check,libbpf-bpf_map_create)
-          ifeq ($(feature-libbpf-bpf_map_create), 1)
-            CFLAGS += -DHAVE_LIBBPF_BPF_MAP_CREATE
-          endif
         else
-          dummy := $(error Error: No libbpf devel library found, please install libbpf-devel);
+          dummy := $(error Error: No libbpf devel library found or older than v1.0, please install/update libbpf-devel);
         endif
       else
         # Libbpf will be built as a static library from tools/lib/bpf.
 	LIBBPF_STATIC := 1
-	CFLAGS += -DHAVE_LIBBPF_BTF__LOAD_FROM_KERNEL_BY_ID
-        CFLAGS += -DHAVE_LIBBPF_BPF_PROG_LOAD
-        CFLAGS += -DHAVE_LIBBPF_BPF_OBJECT__NEXT_PROGRAM
-        CFLAGS += -DHAVE_LIBBPF_BPF_OBJECT__NEXT_MAP
-        CFLAGS += -DHAVE_LIBBPF_BPF_PROGRAM__SET_INSNS
-        CFLAGS += -DHAVE_LIBBPF_BTF__RAW_DATA
-        CFLAGS += -DHAVE_LIBBPF_BPF_MAP_CREATE
       endif
     endif